There are two phrases that Charles C. Dorego’s friends and colleagues use to describe him: “very smart” and “very charming.”

That is why colleagues in the real estate industry are wondering how he finds himself at the center of a corruption scandal that has toppled two of the most powerful politicians in the state: Sheldon Silver, the former Democratic speaker of the State Assembly and Dean G. Skelos, the former Republican majority leader in the State Senate.

Mr. Dorego, the general counsel for one of Manhattan’s biggest developers, Glenwood Management, is an influential figure in real estate circles whose warm smile and easygoing demeanor could disarm even those with whom he disagreed in an industry famous for its bitter rivalries.

But Mr. Dorego also likes to let associates know about the political access he enjoyed to the governor, the mayor and top lawmakers that came from being a major developer who dispensed millions of dollars in political contributions on behalf of Glenwood and its owner, Leonard Litwin.

“Charlie likes access,” said one executive who worked with Mr. Dorego at the Real Estate Board of New York. “He likes to talk about access to politicians.”

Lawyers at Mr. Dorego’s former law firm and several real estate executives all spoke admiringly of Mr. Dorego but declined to be identified for fear of being dragged into the matter.

Mr. Dorego hired an army of lobbyists that eclipsed the contingents from either of real estate’s two most powerful trade groups — the Real Estate Board and the Rent Stabilization Association — ensuring he had the ear of state officials who oversee important housing rules, including a lucrative tax abatement program set to expire next month.

The fate of the housing program, known as 421-a, is critical to Glenwood. The company owns nine Manhattan apartment buildings with a total of nearly 3,000 apartments that receive 421-a tax breaks worth more than $700 million over 20 years. The newest building, Hawthorn Park, overlooks Lincoln Center and features two-bedroom apartments renting for $7,400 a month.

Mr. Dorego, who friends say once considered leaving the law to manage a minor-league baseball team, figures prominently in the federal criminal complaints against Mr. Silver and Mr. Skelos, that involve payoffs, graft, fraud and solicitation of bribes.

In exchange for a non-prosecution agreement, Mr. Dorego in April began cooperating with the Federal Bureau of Investigation and prosecutors in the office of the United States attorney’s office for the Southern District of New York.

Mr. Dorego, whose lawyer did not return calls, has not been charged with any wrongdoing. He is not identified by name in the criminal complaints, but is referred to as CW-1, or cooperating witness, in the complaint against Mr. Skelos and his son, and as “a representative of Developer-1” — which is Glenwood — in the charges against Mr. Silver.

Prosecutors have declined to release a copy of the non-prosecution agreement, which could illuminate which crimes, if any, Mr. Dorego may have committed; why the government chose not to charge him; and how and what he knows about potentially illegal acts by Mr. Silver, Mr. Skelos or others.

Mr. Dorego has had cancer, which friends say returned last fall. It is unclear if that may have affected his decisions in the investigation.

J. Bruce Maffeo, a former top federal prosecutor who is not involved in the case, also noted that “the line between a victim and a co-conspirator is left to the whim of the prosecutor.”

Mr. Dorego is one of three people running Glenwood, which owns at least 26 luxury rental buildings in Manhattan. In recent years, the company’s founder, Leonard Litwin, has turned over the reins to his daughter Carole Litwin Pittelman; Gary Jacob, a longtime executive; and Mr. Dorego, who was responsible for hiring lobbyists and distributing political contributions.

As a young man, Mr. Dorego, who is divorced with two sons, played semiprofessional baseball, according to a partner at his old law firm. Shortly after graduating from Brooklyn Law School in 1984, he joined a law firm headed by Leonard Boxer, a prominent real estate lawyer. The firm later merged with Stroock & Stroock & Lavan, a Manhattan firm with a large real estate practice.

In the early 1990s, Mr. Litwin asked Mr. Boxer if he could “borrow” Mr. Dorego for a project in Arizona, where his grandson, Steven Swarzman, owned a minor-league baseball stadium. After failing to lure the Kansas City Royals there for spring training, the men demolished the stadium in 1994 and erected an apartment building for older people.

Mr. Dorego returned to Stroock for five years, before joining Glenwood in 2001 as a senior executive. He and Mr. Litwin served on the Real Estate Board’s executive committee where Mr. Dorego successfully argued against several major developers, including Related and the Durst Organization, that wanted to sue the city over what they viewed as unfairly high taxes on multifamily rental housing. He managed to maintain good relations with them.

“Charlie’s a good guy,” one real estate lawyer said. “He really is. He doesn’t lie. He always had a big smile on his face. Sometimes you get yourself into a situation with people that you come to regret.”

From the beginning, Mr. Dorego was engaged in politics and power relations, all the while protecting Glenwood’s interests.

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Charles C. Dorego, the general counsel for Glenwood Management, is cooperating with the F.B.I. and prosecutors.CreditCindy Ord/Getty Images

Since 2005, Glenwood has given more than $12 million in political contributions in New York, including donations to Mr. Silver, Mr. Skelos and Gov. Andrew M. Cuomo, a Democrat, according to an analysis by Common Cause New York, which included contributions from related companies and individuals.

Glenwood — along with its affiliates — was the second-largest single political donor to state-level candidates and party committees in 2013, according to an analysis by the New York Public Interest Research Group.

Glenwood’s “business model depends in substantial part on favorable tax abatements and rent regulations that must be periodically renewed” in Albany, according to the criminal complaint against Mr. Skelos.

The complaint as well as the one against Mr. Silver provide another glimpse of Mr. Dorego.

At the insistence of Mr. Skelos, the complaint says, Mr. Dorego arranged for Mr. Skelos’s son Adam to receive a $20,000 commission from a title company for work he did not perform. Mr. Dorego also arranged for a consulting job for Adam Skelos at an environmental firm, in which Mr. Dorego and Mr. Swarzman, Mr. Litwin’s grandson, had ties, according to the complaint. The firm eventually paid Adam a total of $200,000, prosecutors say, and his father used his position to help the company win a government contract.

For Mr. Silver’s part, the complaint filed against him says he asked Mr. Dorego and Glenwood, which owns three buildings in his Manhattan district, to hire a small law firm to handle some property tax work.

Mr. Dorego, the complaint says, was unaware that Mr. Silver collected 25 percent of the fees paid to the firm. The complaint, however, does not indicate what Mr. Dorego thought he would get in return for steering work there.

But a battle in the State Legislature in 2011 over renewing the 421-a tax program as well as rent regulations that govern one million apartments in New York City provide some clues.

Housing and tenant activists wanted major changes to both programs. But the state’s two major real estate organizations were not on the same page.

The Real Estate Board, which is dominated by Manhattan developers, concentrated on extending the 421-a tax abatements, while the Rent Stabilization Association, which represents mostly landlords in the boroughs outside Manhattan, was focused on fending off attempts to eliminate regulations allowing landlords to deregulate apartments and escalate rents.

Mr. Litwin, as head of Glenwood, is one of the rare developers who is a major player in both organizations.

Today, nine Glenwood buildings get 421-a tax benefits, according to New York City records. In exchange for the tax breaks, Glenwood set aside 459 units, a relatively low 15 percent, of the 2,987 apartments for low- and moderate-income households, according to city records and an analysis by the Association for Neighborhood Housing Development.

“Glenwood takes an absurd amount of benefit from the taxpayer’s pocket to boost its bottom line,” said Benjamin Dulchin, executive director of the housing group, which has called for reforming the housing program. “No wonder they use every bit of influence at their disposal.”

Days after Glenwood contributed $1,000 to Mr. Cuomo’s re-election campaign, Mr. Dorego and a lobbyist met in April 2011 with the governor to discuss rent regulation, according to state records.

A short while later, after Glenwood contributed $25,000 to the Senate Republican Campaign Committee, Mr. Dorego met with Mr. Skelos to discuss real estate regulations and legislation affecting Glenwood, the complaint says.

As the legislative session heated up, Mr. Cuomo met one day in June with representatives from two real estate groups, Mr. Dorego and Mr. Jacob, another top Glenwood executive, as well as Mr. Silver and Mr. Skelos.

Two weeks later, Mr. Cuomo had another meeting on rent regulations that included Mr. Dorego and the trade groups.

Though it is common for the groups to meet with top officials in Albany, it was unusual, according to several Real Estate Board members, for Mr. Dorego to attend.

In the end, real estate executives said, Mr. Dorego and the Real Estate Board were successful in lobbying lawmakers to renew the 421-a program.

But the landlords’ association felt betrayed by their allies. The Legislature passed changes to rent laws making it more difficult to deregulate apartments, but they were more painful for landlords outside Manhattan than for companies like Glenwood, which build in Manhattan where rents are already high.

Glenwood was “more aligned with Rebny, so we got hurt,” said Joe Strasberg, the president of the Rent Stabilization Association, referring to the board. “We lost ground on rent regulation.”

With both rent regulations and the tax credit program up for renewal, housing advocates have mounted a strenuous campaign for changes that they say are needed to increase the amount of low-cost housing.

This time, however, the battle playing out in Albany is unfolding without Mr. Dorego, Mr. Silver or Mr. Skelos.

A version of this article appears in print on , on Page A15 of the New York edition with the headline: Real Estate Executive With ‘Access to Politicians’ Is at Center of Scandals. Order Reprints | Today’s Paper | Subscribe